[{"id":34096,"web_url":"https://patchwork.libcamera.org/comment/34096/","msgid":"<174617152149.1586992.3244390573556787841@ping.linuxembedded.co.uk>","date":"2025-05-02T07:38:41","subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Quoting Stefan Klug (2025-04-03 16:49:06)\n> SFINAE is difficult to read and not needed in these cases. Replace it\n> with static_asserts. The idea came from [1] where it is stated:\n> \n> \"The use of enable_if seems misguided to me. SFINAE is useful for the\n> situation where we consider multiple candidates for something (overloads\n> or class template specializations) and try to choose the correct one,\n> without causing compilation to fail.\"\n> \n> [1]: https://stackoverflow.com/questions/62109526/c-friend-template-that-use-sfinae\n> \n> Signed-off-by: Stefan Klug \n> Reviewed-by: Laurent Pinchart \n> \n> ---\n> \n> Changes in v2:\n> - Added this patch\n> \n> Changes in v3:\n> - Left SFINAE in place for the operators as static asserts could cause\n> issues there\n\nBarnabás, did this update resolve your concerns from v2?\n\n\n\n> ---\n> include/libcamera/internal/matrix.h | 19 +++++--------------\n> 1 file changed, 5 insertions(+), 14 deletions(-)\n> \n> diff --git a/include/libcamera/internal/matrix.h b/include/libcamera/internal/matrix.h\n> index a055e6926c94..b9c3d41ef855 100644\n> --- a/include/libcamera/internal/matrix.h\n> +++ b/include/libcamera/internal/matrix.h\n> @@ -19,14 +19,11 @@ namespace libcamera {\n> \n> LOG_DECLARE_CATEGORY(Matrix)\n> \n> -#ifndef __DOXYGEN__\n> -template - std::enable_if_t> * = nullptr>\n> -#else\n> template\n> -#endif /* __DOXYGEN__ */\n> class Matrix\n> {\n> + static_assert(std::is_arithmetic_v, \"Matrix type must be arithmetic\");\n> +\n> public:\n> Matrix()\n> {\n> @@ -123,16 +120,10 @@ Matrix operator*(const Matrix &m, T d)\n> return d * m;\n> }\n> \n> -#ifndef __DOXYGEN__\n> -template - unsigned int R1, unsigned int C1,\n> - unsigned int R2, unsigned int C2,\n> - std::enable_if_t * = nullptr>\n> -#else\n> -template\n> -#endif /* __DOXYGEN__ */\n> -Matrix operator*(const Matrix &m1, const Matrix &m2)\n> +template\n> +constexpr Matrix operator*(const Matrix &m1, const Matrix &m2)\n> {\n> + static_assert(C1 == R2, \"Matrix dimensions must match for multiplication\");\n> Matrix result;\n> \n> for (unsigned int i = 0; i < R1; i++) {\n> -- \n> 2.43.0\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 8633BC327D\n\tfor ;\n\tFri, 2 May 2025 07:38:47 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 8C85F68AD8;\n\tFri, 2 May 2025 09:38:46 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 4EC1B68ACB\n\tfor ;\n\tFri, 2 May 2025 09:38:44 +0200 (CEST)","from pendragon.ideasonboard.com\n\t(cpc89244-aztw30-2-0-cust6594.18-1.cable.virginm.net [86.31.185.195])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 6A726353;\n\tFri, 2 May 2025 09:38:36 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"WFd1goXl\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1746171516;\n\tbh=fp6E4/FV77InC3k2eB/DhvkhybWRPrl7gzHXmMqnyTA=;\n\th=In-Reply-To:References:Subject:From:Cc:To:Date:From;\n\tb=WFd1goXl8UDggdBAkTjhm0wSTooc7MIaZv5/2uSQdGpju3jbXk0zgpVNIj13RMFYM\n\ti7gaWbg+Nu4zu/HnpvCI1kM0sfIECgv2Xv3AB/+d4MNMY572YZ/YSqwWNo12r9/dzM\n\tJDBI5dEEb7KLZ5u1GLlJhKilJ7XZIBhIyjKF3iIU=","Content-Type":"text/plain; charset=\"utf-8\"","MIME-Version":"1.0","Content-Transfer-Encoding":"quoted-printable","In-Reply-To":"<20250403154925.382973-2-stefan.klug@ideasonboard.com>","References":"<20250403154925.382973-1-stefan.klug@ideasonboard.com>\n\t<20250403154925.382973-2-stefan.klug@ideasonboard.com>","Subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","From":"Kieran Bingham ","Cc":"Stefan Klug ,\n\tLaurent Pinchart ","To":"Stefan Klug ,\n\tlibcamera-devel@lists.libcamera.org","Date":"Fri, 02 May 2025 08:38:41 +0100","Message-ID":"<174617152149.1586992.3244390573556787841@ping.linuxembedded.co.uk>","User-Agent":"alot/0.10","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":34118,"web_url":"https://patchwork.libcamera.org/comment/34118/","msgid":"<790ac02c-1cae-483e-8385-8bab1030f3a4@ideasonboard.com>","date":"2025-05-02T13:58:13","subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","submitter":{"id":216,"url":"https://patchwork.libcamera.org/api/people/216/","name":"Barnabás Pőcze","email":"barnabas.pocze@ideasonboard.com"},"content":"Hi\n\n\n2025. 05. 02. 9:38 keltezéssel, Kieran Bingham írta:\n> Quoting Stefan Klug (2025-04-03 16:49:06)\n>> SFINAE is difficult to read and not needed in these cases. Replace it\n>> with static_asserts. The idea came from [1] where it is stated:\n>>\n>> \"The use of enable_if seems misguided to me. SFINAE is useful for the\n>> situation where we consider multiple candidates for something (overloads\n>> or class template specializations) and try to choose the correct one,\n>> without causing compilation to fail.\"\n>>\n>> [1]: https://stackoverflow.com/questions/62109526/c-friend-template-that-use-sfinae\n>>\n>> Signed-off-by: Stefan Klug \n>> Reviewed-by: Laurent Pinchart \n>>\n>> ---\n>>\n>> Changes in v2:\n>> - Added this patch\n>>\n>> Changes in v3:\n>> - Left SFINAE in place for the operators as static asserts could cause\n>> issues there\n> \n> Barnabás, did this update resolve your concerns from v2?\n\nYes, although as I have mentioned, I think it was fine as is because it\nis an internal thing, and it can be changed arbitrarily if needed.\n\n\nRegards,\nBarnabás Pőcze\n\n> \n> \n> \n>> ---\n>> include/libcamera/internal/matrix.h | 19 +++++--------------\n>> 1 file changed, 5 insertions(+), 14 deletions(-)\n>>\n>> diff --git a/include/libcamera/internal/matrix.h b/include/libcamera/internal/matrix.h\n>> index a055e6926c94..b9c3d41ef855 100644\n>> --- a/include/libcamera/internal/matrix.h\n>> +++ b/include/libcamera/internal/matrix.h\n>> @@ -19,14 +19,11 @@ namespace libcamera {\n>> \n>> LOG_DECLARE_CATEGORY(Matrix)\n>> \n>> -#ifndef __DOXYGEN__\n>> -template> - std::enable_if_t> * = nullptr>\n>> -#else\n>> template\n>> -#endif /* __DOXYGEN__ */\n>> class Matrix\n>> {\n>> + static_assert(std::is_arithmetic_v, \"Matrix type must be arithmetic\");\n>> +\n>> public:\n>> Matrix()\n>> {\n>> @@ -123,16 +120,10 @@ Matrix operator*(const Matrix &m, T d)\n>> return d * m;\n>> }\n>> \n>> -#ifndef __DOXYGEN__\n>> -template> - unsigned int R1, unsigned int C1,\n>> - unsigned int R2, unsigned int C2,\n>> - std::enable_if_t * = nullptr>\n>> -#else\n>> -template\n>> -#endif /* __DOXYGEN__ */\n>> -Matrix operator*(const Matrix &m1, const Matrix &m2)\n>> +template\n>> +constexpr Matrix operator*(const Matrix &m1, const Matrix &m2)\n>> {\n>> + static_assert(C1 == R2, \"Matrix dimensions must match for multiplication\");\n>> Matrix result;\n>> \n>> for (unsigned int i = 0; i < R1; i++) {\n>> -- \n>> 2.43.0\n>>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 95907C327D\n\tfor ;\n\tFri, 2 May 2025 13:58:19 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 8D16968ADC;\n\tFri, 2 May 2025 15:58:18 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 5B4BF68AD3\n\tfor ;\n\tFri, 2 May 2025 15:58:17 +0200 (CEST)","from [192.168.33.18] (185.221.143.50.nat.pool.zt.hu\n\t[185.221.143.50])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 32C61353;\n\tFri, 2 May 2025 15:58:09 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"Kj65+UTQ\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1746194289;\n\tbh=7Nu+yvK/Ht+N5MMoMVYdoGLMPNoxaWHE0gY29SCT+HE=;\n\th=Date:Subject:To:Cc:References:From:In-Reply-To:From;\n\tb=Kj65+UTQ6eiE+4nRc5LlSlIZfqDXBI3umULGlBTEwJ4E9TmUZ4CAdzvl4qJdPOPfu\n\t+qQC3yebsAM5KmNEgv1TlASdv5JYTwSTh2fBdYAmXkjslvrJM0yYoX1I51rUOceH2G\n\tQwkUxkFRzIMEjvgodCnX1jbpTgIzmfy7F42YFs1w=","Message-ID":"<790ac02c-1cae-483e-8385-8bab1030f3a4@ideasonboard.com>","Date":"Fri, 2 May 2025 15:58:13 +0200","MIME-Version":"1.0","User-Agent":"Mozilla Thunderbird","Subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","To":"Kieran Bingham ","Cc":"Laurent Pinchart ,\n\tlibcamera-devel@lists.libcamera.org,\n\tStefan Klug ","References":"<20250403154925.382973-1-stefan.klug@ideasonboard.com>\n\t<20250403154925.382973-2-stefan.klug@ideasonboard.com>\n\t<174617152149.1586992.3244390573556787841@ping.linuxembedded.co.uk>","From":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","Content-Language":"en-US, hu-HU","In-Reply-To":"<174617152149.1586992.3244390573556787841@ping.linuxembedded.co.uk>","Content-Type":"text/plain; charset=UTF-8; format=flowed","Content-Transfer-Encoding":"8bit","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":34127,"web_url":"https://patchwork.libcamera.org/comment/34127/","msgid":"<174629836225.2902011.10608325476465338505@ping.linuxembedded.co.uk>","date":"2025-05-03T18:52:42","subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","submitter":{"id":4,"url":"https://patchwork.libcamera.org/api/people/4/","name":"Kieran Bingham","email":"kieran.bingham@ideasonboard.com"},"content":"Quoting Barnabás Pőcze (2025-05-02 14:58:13)\n> Hi\n> \n> \n> 2025. 05. 02. 9:38 keltezéssel, Kieran Bingham írta:\n> > Quoting Stefan Klug (2025-04-03 16:49:06)\n> >> SFINAE is difficult to read and not needed in these cases. Replace it\n> >> with static_asserts. The idea came from [1] where it is stated:\n> >>\n> >> \"The use of enable_if seems misguided to me. SFINAE is useful for the\n> >> situation where we consider multiple candidates for something (overloads\n> >> or class template specializations) and try to choose the correct one,\n> >> without causing compilation to fail.\"\n> >>\n> >> [1]: https://stackoverflow.com/questions/62109526/c-friend-template-that-use-sfinae\n> >>\n> >> Signed-off-by: Stefan Klug \n> >> Reviewed-by: Laurent Pinchart \n> >>\n> >> ---\n> >>\n> >> Changes in v2:\n> >> - Added this patch\n> >>\n> >> Changes in v3:\n> >> - Left SFINAE in place for the operators as static asserts could cause\n> >> issues there\n> > \n> > Barnabás, did this update resolve your concerns from v2?\n> \n> Yes, although as I have mentioned, I think it was fine as is because it\n> is an internal thing, and it can be changed arbitrarily if needed.\n\nDoes that mean this patch can have your RB tag ?\n\n--\nKieran\n\n\n> \n> \n> Regards,\n> Barnabás Pőcze\n> \n> > \n> > \n> > \n> >> ---\n> >> include/libcamera/internal/matrix.h | 19 +++++--------------\n> >> 1 file changed, 5 insertions(+), 14 deletions(-)\n> >>\n> >> diff --git a/include/libcamera/internal/matrix.h b/include/libcamera/internal/matrix.h\n> >> index a055e6926c94..b9c3d41ef855 100644\n> >> --- a/include/libcamera/internal/matrix.h\n> >> +++ b/include/libcamera/internal/matrix.h\n> >> @@ -19,14 +19,11 @@ namespace libcamera {\n> >> \n> >> LOG_DECLARE_CATEGORY(Matrix)\n> >> \n> >> -#ifndef __DOXYGEN__\n> >> -template >> - std::enable_if_t> * = nullptr>\n> >> -#else\n> >> template\n> >> -#endif /* __DOXYGEN__ */\n> >> class Matrix\n> >> {\n> >> + static_assert(std::is_arithmetic_v, \"Matrix type must be arithmetic\");\n> >> +\n> >> public:\n> >> Matrix()\n> >> {\n> >> @@ -123,16 +120,10 @@ Matrix operator*(const Matrix &m, T d)\n> >> return d * m;\n> >> }\n> >> \n> >> -#ifndef __DOXYGEN__\n> >> -template >> - unsigned int R1, unsigned int C1,\n> >> - unsigned int R2, unsigned int C2,\n> >> - std::enable_if_t * = nullptr>\n> >> -#else\n> >> -template\n> >> -#endif /* __DOXYGEN__ */\n> >> -Matrix operator*(const Matrix &m1, const Matrix &m2)\n> >> +template\n> >> +constexpr Matrix operator*(const Matrix &m1, const Matrix &m2)\n> >> {\n> >> + static_assert(C1 == R2, \"Matrix dimensions must match for multiplication\");\n> >> Matrix result;\n> >> \n> >> for (unsigned int i = 0; i < R1; i++) {\n> >> -- \n> >> 2.43.0\n> >>\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 51B92C3226\n\tfor ;\n\tSat, 3 May 2025 18:52:47 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 7189868B25;\n\tSat, 3 May 2025 20:52:46 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 57587617CB\n\tfor ;\n\tSat, 3 May 2025 20:52:45 +0200 (CEST)","from pendragon.ideasonboard.com\n\t(cpc89244-aztw30-2-0-cust6594.18-1.cable.virginm.net [86.31.185.195])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 6E12455;\n\tSat, 3 May 2025 20:52:36 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"bA3JKJ1w\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1746298356;\n\tbh=QLFZ0aqteNCiBtNxC3oTO4XAMay+NIZ2gv2P2XgVG3Y=;\n\th=In-Reply-To:References:Subject:From:Cc:To:Date:From;\n\tb=bA3JKJ1wGAjSqk+FIE8F9tkFE9l0GlS+CnEu71FakXZzZYXoU0gvDPN/1zdBiGIIK\n\tLcwipRzsh5UVR4gN54bAKo03uEenExF0Rc8jzfXcpc1kVCNgKEaE3Fqs5FWQQuiMfT\n\tB28/nSvxcag4/p3qK9MWBTk4RwG8QzJhHPg+8zSM=","Content-Type":"text/plain; charset=\"utf-8\"","MIME-Version":"1.0","Content-Transfer-Encoding":"quoted-printable","In-Reply-To":"<790ac02c-1cae-483e-8385-8bab1030f3a4@ideasonboard.com>","References":"<20250403154925.382973-1-stefan.klug@ideasonboard.com>\n\t<20250403154925.382973-2-stefan.klug@ideasonboard.com>\n\t<174617152149.1586992.3244390573556787841@ping.linuxembedded.co.uk>\n\t<790ac02c-1cae-483e-8385-8bab1030f3a4@ideasonboard.com>","Subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","From":"Kieran Bingham ","Cc":"Laurent Pinchart ,\n\tlibcamera-devel@lists.libcamera.org,\n\tStefan Klug ","To":"=?utf-8?q?Barnab=C3=A1s_P=C5=91cze?= ","Date":"Sat, 03 May 2025 19:52:42 +0100","Message-ID":"<174629836225.2902011.10608325476465338505@ping.linuxembedded.co.uk>","User-Agent":"alot/0.10","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":34138,"web_url":"https://patchwork.libcamera.org/comment/34138/","msgid":"","date":"2025-05-07T15:31:42","subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","submitter":{"id":17,"url":"https://patchwork.libcamera.org/api/people/17/","name":"Paul Elder","email":"paul.elder@ideasonboard.com"},"content":"On Thu, Apr 03, 2025 at 05:49:06PM +0200, Stefan Klug wrote:\n> SFINAE is difficult to read and not needed in these cases. Replace it\n> with static_asserts. The idea came from [1] where it is stated:\n> \n> \"The use of enable_if seems misguided to me. SFINAE is useful for the\n> situation where we consider multiple candidates for something (overloads\n> or class template specializations) and try to choose the correct one,\n> without causing compilation to fail.\"\n> \n> [1]: https://stackoverflow.com/questions/62109526/c-friend-template-that-use-sfinae\n> \n> Signed-off-by: Stefan Klug \n> Reviewed-by: Laurent Pinchart \n\nReviewed-by: Paul Elder \n\n> \n> ---\n> \n> Changes in v2:\n> - Added this patch\n> \n> Changes in v3:\n> - Left SFINAE in place for the operators as static asserts could cause\n> issues there\n> ---\n> include/libcamera/internal/matrix.h | 19 +++++--------------\n> 1 file changed, 5 insertions(+), 14 deletions(-)\n> \n> diff --git a/include/libcamera/internal/matrix.h b/include/libcamera/internal/matrix.h\n> index a055e6926c94..b9c3d41ef855 100644\n> --- a/include/libcamera/internal/matrix.h\n> +++ b/include/libcamera/internal/matrix.h\n> @@ -19,14 +19,11 @@ namespace libcamera {\n> \n> LOG_DECLARE_CATEGORY(Matrix)\n> \n> -#ifndef __DOXYGEN__\n> -template -\t std::enable_if_t> * = nullptr>\n> -#else\n> template\n> -#endif /* __DOXYGEN__ */\n> class Matrix\n> {\n> +\tstatic_assert(std::is_arithmetic_v, \"Matrix type must be arithmetic\");\n> +\n> public:\n> \tMatrix()\n> \t{\n> @@ -123,16 +120,10 @@ Matrix operator*(const Matrix &m, T d)\n> \treturn d * m;\n> }\n> \n> -#ifndef __DOXYGEN__\n> -template -\t unsigned int R1, unsigned int C1,\n> -\t unsigned int R2, unsigned int C2,\n> -\t std::enable_if_t * = nullptr>\n> -#else\n> -template\n> -#endif /* __DOXYGEN__ */\n> -Matrix operator*(const Matrix &m1, const Matrix &m2)\n> +template\n> +constexpr Matrix operator*(const Matrix &m1, const Matrix &m2)\n> {\n> +\tstatic_assert(C1 == R2, \"Matrix dimensions must match for multiplication\");\n> \tMatrix result;\n> \n> \tfor (unsigned int i = 0; i < R1; i++) {\n> -- \n> 2.43.0\n>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 62FDAC3226\n\tfor ;\n\tWed, 7 May 2025 15:31:48 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 1B51A68B31;\n\tWed, 7 May 2025 17:31:48 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[213.167.242.64])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 15F3368AD8\n\tfor ;\n\tWed, 7 May 2025 17:31:47 +0200 (CEST)","from pyrite.rasen.tech (unknown\n\t[IPv6:2001:861:3a80:3300:4f2f:8c2c:b3ef:17d4])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id 91DD0C59;\n\tWed, 7 May 2025 17:31:35 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; dkim=pass (1024-bit key;\n\tunprotected) header.d=ideasonboard.com header.i=@ideasonboard.com\n\theader.b=\"G2v5wUXh\"; dkim-atps=neutral","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com;\n\ts=mail; t=1746631895;\n\tbh=4qEfszDTyVXAyR+Vn0A+4lf54SMSqpltckeO08Q7OVE=;\n\th=Date:From:To:Cc:Subject:References:In-Reply-To:From;\n\tb=G2v5wUXhmBrp8DxnKi0La9nbaAbNmQ98/RUAkzBrLerjz6qW/GxNlVxzufhnQW+J2\n\t0rz3Z8OOt3ioEQl5lY0eC7CQFIntD8nMqu7cy8VM/6O2uKuiGhiHTbWY/S+z/eYlXS\n\tyjO2l1f5twynK1hEzse12dfW2jhWQnM2YnUsJrsg=","Date":"Wed, 7 May 2025 17:31:42 +0200","From":"Paul Elder ","To":"Stefan Klug ","Cc":"libcamera-devel@lists.libcamera.org,\n\tLaurent Pinchart ","Subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","Message-ID":"","References":"<20250403154925.382973-1-stefan.klug@ideasonboard.com>\n\t<20250403154925.382973-2-stefan.klug@ideasonboard.com>","MIME-Version":"1.0","Content-Type":"text/plain; charset=us-ascii","Content-Disposition":"inline","In-Reply-To":"<20250403154925.382973-2-stefan.klug@ideasonboard.com>","X-BeenThere":"libcamera-devel@lists.libcamera.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Errors-To":"libcamera-devel-bounces@lists.libcamera.org","Sender":"\"libcamera-devel\" "}},{"id":34159,"web_url":"https://patchwork.libcamera.org/comment/34159/","msgid":"<5b08e2ca-6fe2-4665-8f6f-8fa24caf994e@ideasonboard.com>","date":"2025-05-08T06:39:43","subject":"Re: [PATCH v3 01/16] libcamera: matrix: Replace SFINAE with\n\tstatic_asserts","submitter":{"id":216,"url":"https://patchwork.libcamera.org/api/people/216/","name":"Barnabás Pőcze","email":"barnabas.pocze@ideasonboard.com"},"content":"2025. 05. 03. 20:52 keltezéssel, Kieran Bingham írta:\n> Quoting Barnabás Pőcze (2025-05-02 14:58:13)\n>> Hi\n>>\n>>\n>> 2025. 05. 02. 9:38 keltezéssel, Kieran Bingham írta:\n>>> Quoting Stefan Klug (2025-04-03 16:49:06)\n>>>> SFINAE is difficult to read and not needed in these cases. Replace it\n>>>> with static_asserts. The idea came from [1] where it is stated:\n>>>>\n>>>> \"The use of enable_if seems misguided to me. SFINAE is useful for the\n>>>> situation where we consider multiple candidates for something (overloads\n>>>> or class template specializations) and try to choose the correct one,\n>>>> without causing compilation to fail.\"\n>>>>\n>>>> [1]: https://stackoverflow.com/questions/62109526/c-friend-template-that-use-sfinae\n>>>>\n>>>> Signed-off-by: Stefan Klug \n>>>> Reviewed-by: Laurent Pinchart \n>>>>\n>>>> ---\n>>>>\n>>>> Changes in v2:\n>>>> - Added this patch\n>>>>\n>>>> Changes in v3:\n>>>> - Left SFINAE in place for the operators as static asserts could cause\n>>>> issues there\n>>>\n>>> Barnabás, did this update resolve your concerns from v2?\n>>\n>> Yes, although as I have mentioned, I think it was fine as is because it\n>> is an internal thing, and it can be changed arbitrarily if needed.\n> \n> Does that mean this patch can have your RB tag ?\n\nReviewed-by: Barnabás Pőcze \n\n\n> \n> --\n> Kieran\n> \n> \n>>\n>>\n>> Regards,\n>> Barnabás Pőcze\n>>\n>>>\n>>>\n>>>\n>>>> ---\n>>>> include/libcamera/internal/matrix.h | 19 +++++--------------\n>>>> 1 file changed, 5 insertions(+), 14 deletions(-)\n>>>>\n>>>> diff --git a/include/libcamera/internal/matrix.h b/include/libcamera/internal/matrix.h\n>>>> index a055e6926c94..b9c3d41ef855 100644\n>>>> --- a/include/libcamera/internal/matrix.h\n>>>> +++ b/include/libcamera/internal/matrix.h\n>>>> @@ -19,14 +19,11 @@ namespace libcamera {\n>>>> \n>>>> LOG_DECLARE_CATEGORY(Matrix)\n>>>> \n>>>> -#ifndef __DOXYGEN__\n>>>> -template>>> - std::enable_if_t> * = nullptr>\n>>>> -#else\n>>>> template\n>>>> -#endif /* __DOXYGEN__ */\n>>>> class Matrix\n>>>> {\n>>>> + static_assert(std::is_arithmetic_v, \"Matrix type must be arithmetic\");\n>>>> +\n>>>> public:\n>>>> Matrix()\n>>>> {\n>>>> @@ -123,16 +120,10 @@ Matrix operator*(const Matrix &m, T d)\n>>>> return d * m;\n>>>> }\n>>>> \n>>>> -#ifndef __DOXYGEN__\n>>>> -template>>> - unsigned int R1, unsigned int C1,\n>>>> - unsigned int R2, unsigned int C2,\n>>>> - std::enable_if_t * = nullptr>\n>>>> -#else\n>>>> -template\n>>>> -#endif /* __DOXYGEN__ */\n>>>> -Matrix operator*(const Matrix &m1, const Matrix &m2)\n>>>> +template\n>>>> +constexpr Matrix operator*(const Matrix &m1, const Matrix &m2)\n>>>> {\n>>>> + static_assert(C1 == R2, \"Matrix dimensions must match for multiplication\");\n>>>> Matrix result;\n>>>> \n>>>> for (unsigned int i = 0; i < R1; i++) {\n>>>> -- \n>>>> 2.43.0\n>>>>\n>>","headers":{"Return-Path":"","X-Original-To":"parsemail@patchwork.libcamera.org","Delivered-To":"parsemail@patchwork.libcamera.org","Received":["from lancelot.ideasonboard.com (lancelot.ideasonboard.com\n\t[92.243.16.209])\n\tby patchwork.libcamera.org (Postfix) with ESMTPS id 02BE4C3226\n\tfor ;\n\tThu, 8 May 2025 06:39:51 +0000 (UTC)","from lancelot.ideasonboard.com (localhost [IPv6:::1])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTP id 364FE68B45;\n\tThu, 8 May 2025 08:39:50 +0200 (CEST)","from perceval.ideasonboard.com (perceval.ideasonboard.com\n\t[IPv6:2001:4b98:dc2:55:216:3eff:fef7:d647])\n\tby lancelot.ideasonboard.com (Postfix) with ESMTPS id 0E2856175D\n\tfor ;\n\tThu, 8 May 2025 08:39:48 +0200 (CEST)","from [192.168.33.16] (185.221.141.56.nat.pool.zt.hu\n\t[185.221.141.56])\n\tby perceval.ideasonboard.com (Postfix) with ESMTPSA id D2474446;\n\tThu, 8 May 2025 08:39:35 +0200 (CEST)"],"Authentication-Results":"lancelot.ideasonboard.com; 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